The present invention relates to analysis and creation of part programs used in coordinate and surface texture measurement. The present invention more particularly relates to a part program analysis method and apparatus and a part program creation method and apparatus, in which various measurement information or measurement conditions are extracted from a part program used for actual measurement, and the extracted information is stored as general-purpose information for constructive use in an associated coordinate and surface texture measurement device or other three-dimensional coordinate measurement devices.
Three-dimensional coordinate measurement devices and surface texture measurement devices are measurement devices for measuring and evaluating, primarily, the dimensions and the shape of a workpiece. However, by replacing the measurement probe, those devices can be used to simultaneously measure and evaluate the surface roughness of a workpiece. Three-dimensional coordinate measurement devices are employed in a wide range of industrial fields because many types of measurement probes such as a touch-trigger sensor, camera, or laser sensor can be used with such devices.
The operation of a three-dimensional coordinate measurement device and surface texture measurement device is defined by information written in a measurement part program. In a computer numerical control (CNC) three-dimensional coordinate measurement device, the operation is automatically controlled according to an input part program.
Typically, a part program integrates commands concerning measurement operation such as a probe change command and a measurement command, and commands concerning measurement device control such as a positioning speed command and a measuring speed command. In order to precisely and efficiently perform a measurement operation, the part program must include commands appropriate for both the workpiece, i.e., the object of measurement, and the measurement device, i.e., the object of control.
Conventionally, methods for creating a measurement part program include online teaching, in which an operator controls the three-dimensional coordinate measurement device using an operation panel to teach measurement procedures, and offline teaching, in which electronic diagram information such as CAD data of the workpiece is used to teach the measurement procedures without moving the actual three-dimensional coordinate measurement device. Compared to online teaching by an operator, offline teaching through CAD data is especially useful when performing in-line measurement because the measurement device need not be tied up while a measurement part program is created.
Normally, in online teaching, the operator can easily determine the positions and items of measurement based on the workpiece diagrams and the measurement operation instructions. However, the operator usually determines the specific measurement procedures, such as the selection of measurement probe, setting of measuring speed, and number of points to use for measuring each item, based on his or her skill and experience. An operator with less skill and experience must therefore repeatedly modify and test a part program before completing a high-quality part program.
In offline teaching, on the other hand, the offline programming tool creates a measurement part program using input data such as the workpiece diagram data and the measurement operation instruction data, and the integrated databases inside the programming tool such as a database on the specification of the measurement device and a database on measurement conditions and methods. The raw part program created in this way is, in general, far from being an optimal part program. In order to complete a high-quality part program, it is necessary to optimize the measurement path and the measurement procedures such as the selection of measurement probe, setting of measuring speed, and number of measuring points. Accordingly, it is necessary to repetitively perform the processes of conducting simulations and test measurements, and of modifying the part program according to the measurement results.
As explained above, in conventional methods for creating a part program for three-dimensional coordinate measurement, whether it be online teaching by an operator or offline teaching using CAD data, there is a problem that test measurements and part program modifications must be repeated to create a high-quality part program. Further, while the knowledge and know-how concerning measurement procedures obtained through the above-described processes for completing a high-quality part program can improve the skill and experience of a single operator, it is a significant problem that this knowledge and know-how can not readily be shared by a group of people.
The present invention was conceived in light of the existing problems. The object of the present invention is to analyze a measurement part program, especially a practiced measurement part program used after completion of modification and tests, and to extract measurement information or measurement conditions which reflect the operator""s skills, experience, and know-how, such that the extracted information can be used as a database for subsequent measurements. By systematically correlating this extracted measurement information or measurement conditions to information such as probe information, measurement device information, workpiece material information, and machining method information, commands appropriate for both the workpiece, i.e., the object of measurement, and the measurement device, i.e., the object of control, can be integrated in a part program from the initial stages of the part program creation. By referencing the accumulated database obtained as feedback, a measurement part program optimal for each case can be instantly and automatically programmed. Furthermore, such a database can also supply data for measurement devices other than the original measurement device. The database can be shared among all the measurement devices which are the members constituting a CIM (computer integrated manufacturing system). Much of the program modification and editing can thereby be performed based on interactions with the database, without completely depending on operator skill.
The present invention was created in view of the above objects. In coordinate and surface texture measurement in which measurement control is performed by a part program, the present invention comprises a measurement method analyzing means or step for analyzing a part program to extract measurement information or measurement condition, and a storing means or step for rewritably storing said measurement condition.
Further, in coordinate and surface texture measurement in which measurement control is performed by a part program, the present invention may comprise a measurement method analyzing means or step for analyzing a part program to extract measurement information or measurement condition for each item measurement, and a storing means or step for rewritably storing said measurement condition corresponding to each item measurement.
Still further, in coordinate and surface texture measurement in which measurement control is performed by a part program, the present invention may comprise a measurement method analyzing means or step for receiving an input of a measurement part program and workpiece machining information data, and for analyzing said practiced measurement part program to extract measurement information or measurement condition for each item measurement; a database producing means or step for converting said measurement information or measurement condition extracted for each item measurement into a database necessary for creating a part program; and a database for creating a part program, which rewritably stores said measurement condition corresponding to each item measurement.
In the present invention, the database may be a relational database.
According to the present invention, a part program for coordinate and surface texture measurement may be created referring to the database.
Moreover, an apparatus for generating a part program for coordinate and surface texture measurement according to the present invention may analyze data of the database for use in determining of a measurement condition, and output or display the result of the analysis.
Furthermore, an apparatus for generating a part program for coordinate and surface texture measurement according to the present invention may analyze data of the database to automatically determine a measurement condition.
As described above, in a three-dimensional coordinate measurement system according to the present invention, the measurement method of a completed part program used for actual measurement in work sites can be analyzed to extract necessary measurement conditions, and the extracted conditions can be reflected in the database used when creating a part program. It is therefore possible to reliably extract measurement conditions, including know-how of skilled operators and modifications of part programs achieved only through simulations or test measurements, and to produce a database with those extracted conditions. In this way, a knowledge database which is extremely useful for database creation can be easily configured.
According to the present invention, the measurement conditions extracted from part programs created for each necessary measurement are accumulated while being systematically correlated to probe information, measurement device information, workpiece material information, workpiece machining information, and the like. In this way, the measurement conditions can be integrated into the database in a manner that takes advantage of the accumulated skill, experience, and know-how of individual operators.
With this arrangement, commands appropriate to both the workpiece, i.e., the object of measurement, and to the measurement device, i.e., the object of control, can be integrated in a part program from the initial stages of the part program is creation. By referencing the accumulated database obtained as a feedback, an optimal measurement part program for each case can be instantly and automatically programmed. Variances in measurement conditions stemming from differences among individual operators can thereby be eliminated, and measurement can be efficiently made under optimal measurement conditions. As a result, measurement accuracy can be maintained or further enhanced, and measurement time can be reduced.
Furthermore, a part program created for a particular measurement device may be adopted in another measurement device having a different specification. In such a case, by using each of the modularized measurement conditions, a new measurement part program can be automatically produced while taking into account the differences in specifications between the measurement device for which the part program was created and the new measurement device to be used. For example, the measurement condition data accumulated using an old model measurement device, except for points that have been changed, can be used as information for a new model measurement device. By inputting new information for only the changed points, automatic programming can be performed reflecting the previously accumulated data, thereby facilitating reprogramming.